CVE-2017-2397 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3 is affected. The issue involves the "Accounts" component. It allows physically proximate attackers to discover an Apple ID by reading an iCloud authentication prompt on the lock screen.
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Analysis
by VulDB Data Team • 11/20/2022
The vulnerability identified as CVE-2017-2397 represents a significant security flaw in Apple's iOS operating system affecting versions prior to 10.3. This issue resides within the Accounts component of the iOS framework and demonstrates a critical weakness in the device's lock screen security model. The vulnerability specifically targets the iCloud authentication prompt mechanism that appears when users attempt to access iCloud services, creating an unintended information disclosure channel that compromises user privacy and account security.
The technical nature of this vulnerability stems from insufficient access controls and authentication prompt handling within the iOS lock screen environment. Attackers with physical proximity to a locked iOS device can observe and potentially exploit the iCloud authentication prompt that appears on screen during account access attempts. This flaw does not require any special privileges or complex exploitation techniques, making it particularly dangerous as it can be leveraged by anyone who has physical access to the target device. The vulnerability operates at the system level where authentication prompts are displayed, bypassing normal security boundaries that should protect sensitive account information from unauthorized observation.
From an operational impact perspective, this vulnerability creates a direct pathway for attackers to obtain Apple ID credentials through passive observation of authentication prompts. The risk is particularly severe for users who frequently access iCloud services and may leave their devices unattended in public spaces or shared environments. The vulnerability essentially transforms the lock screen into an information leakage point where sensitive authentication data becomes visible to anyone who can observe the device screen. This represents a violation of the fundamental security principle that authentication information should remain protected even when a device is locked, as outlined in various security frameworks including the NIST Cybersecurity Framework.
The vulnerability aligns with CWE-200, which addresses "Information Exposure," and demonstrates how improper handling of authentication prompts can lead to unauthorized information disclosure. From an ATT&CK framework perspective, this vulnerability maps to T1552.001, "Credentials In Files," and T1552.006, "Credentials in Registry," as it involves the exposure of authentication credentials through screen display mechanisms rather than traditional file or registry storage methods. The physical proximity requirement reduces the attack surface but does not eliminate the risk entirely, as many users may not be aware of the exposure risk or may leave devices unattended in insecure locations.
Mitigation strategies for CVE-2017-2397 primarily involve upgrading to iOS version 10.3 or later, where Apple implemented proper access controls and authentication prompt handling that prevents the display of sensitive account information on the lock screen. Users should also employ additional security measures such as enabling strong passcodes, utilizing auto-lock features, and avoiding leaving devices unattended in public spaces. Organizations should ensure their iOS device management policies include mandatory upgrade requirements and regular security assessments to prevent exploitation of known vulnerabilities. The fix implemented by Apple addresses the core issue by modifying the authentication prompt behavior to ensure that sensitive account information is not displayed when the device is locked, thereby protecting against this specific class of information disclosure attacks.